"We also examined whether genetic risk for Alzheimer’s Disease or brain volumes suggestive of early neurodegeneration were associated with a reduction in slow-wave sleep. We found that a genetic risk factor for Alzheimer’s disease, but not brain volume, was associated with accelerated declines in slow wave sleep"
This sounds like the arrow of causation is pointing the other way.
The study found that []longer[] time spent in bed (TIB) was associated with significantly []increased[] dementia risk. Those in bed for more than 8 hours were far more likely to show a cognitive decline during a Mini Mental State Examination (MMSE)
[...]
The time individuals went to bed was also highlighted by researchers as a critical contributing factor [...] The research paper stated that “every 1 hour advance in bedtime [before 10 pm] was associated with a 25% increased risk of dementia.”
This sounds like the arrow of causation is pointing the other way.